Saturday 31 March 2007 18.57 EDT
First published on Saturday 31 March 2007 18.57 EDT

"Sometimes the 'Don't be evil' policy leads to many discussions about what exactly is evil. One thing we know is that people can make better decisions with better information. Google is a useful tool in people's lives. There are extreme cases, we're told, when Google has saved people's lives." Sergey Brin, Google founder, interviewed in Playboy, September 2004

As the internet enters its second decade as a mass medium, it's worth looking back at one of the old saws that was bandied around in the covered-wagon days, when Californian sages made gnomic pronouncements about the future and the rest of the world repeated them at dinner parties. "The net treats censorship as damage and routes around it." These are the words of John Gilmore, radical libertarian, Sun Microsystems employee number five and bona fide west-coast guru-gazillionaire, and for much of the last 10 years they've been repeated as part of the founding story of the internet, along with a gloss about the net's inception as a military communications network designed to withstand partial destruction by nuclear attack.

In a technical sense, Gilmore (who was talking to a Time magazine journalist in 1993) has been proved right. The internet has provided an efficient conduit for people to share all manner of information other people don't want them to, whether those people are government whistle-blowers, child pornographers, political dissidents, intellectual property pirates or terrorists. From the Drudge Report to beheading videos, censorship is being successfully circumvented around the globe. Looked on from the neutral standpoint adopted by network engineers, this is proof of a robust system. Ethical or political judgements about the content of the information flowing through the networks aren't relevant. It's all data. We should celebrate.

However, around the world, people have also discovered that, despite the abstractions of network architecture and the nostrums of boosters who predicted a "new economy" free of material constraints, the internet is also a physical thing, which has its existence on real telephone lines, internet service provider (ISP) routers, undersea fibre-optic lines and hard drives humming under tangible desks. And it's used by people sitting in real offices with real doors that can be broken down by all-too-real police if the information they're sharing contravenes local laws - and in some cases even if they don't, but some foreign power strong-arms their government, as happened in Sweden in May 2006, when US diplomats incited a police raid on an ISP hosting a popular file-sharing service called the Pirate Bay. The internet's ability to route round censorship has the character of an ideal rather than a reality, a theoretical property.

No one understands this better than the Chinese journalist Shi Tao, who in April 2005 received a 10-year prison sentence for "divulging state secrets abroad". A translation of court proceedings showed that Yahoo! Holdings (Hong Kong), a subsidiary of the American search corporation, had given information to Chinese state investigators allowing them to link him to re-postings on foreign-based websites of an internal message the authorities sent to his newspaper regarding coverage of the 15th anniversary of the Tiananmen Square massacre.

Yahoo!, Google and other internet giants have argued that cooperation with state censorship is the price of doing business in China. With the hypertrophy of the Chinese economy, the financial temptations have proved too great, even for a generation of dotcom companies built on the barefoot idealism of their young staff. Google's oft-quoted motto is "Don't be evil", which might have sounded cool in a Stanford coffee bar, but has lately become something of an international sick joke.

The Chinese government runs one of the most determined and best- resourced censorship operations in the world. In recent years, prison sentences have been handed down for activities such as downloading material from Falun Gong websites or "endangering state security" by participating in pro-democracy discussion forums. This censorship effort relies partly on a large number of human monitors, and partly on technological means, often built and configured by suppliers outside China. For example, Skype, the internet telephone company recently bought by eBay, has admitted incorporating censorship functions into its Chinese-language service.

Search technology (the current darling of the stock market) plays a major role in this. A research project by three universities, known as the OpenNet initiative, routed search requests through Chinese computers using Google, Yahoo! and popular Chinese search engines such as Baidu. They found that searches on many "sensitive" words were summarily cut off. "Freedom", "Taiwan", "Falun Gong" and various terms leading to material critical of the Communist party were routinely unavailable.

Whether in China or Chicago, we're now living in a world where access to information is partly controlled by private corporations, whose wish to "comply with local regulation" may involve many layers of hidden decision-making about what we can see, read and hear. Lack of transparency in the process by which search results are produced means that we don't tend to see messages saying "You have been banned by the government from visiting this site", or "Someone will sue us if we let you see this." Instead we get "host not found" or no error message at all, just a timed-out connection or a crash we might attribute to some other cause. This is invisible censorship, hard to detect, hard to prove. In Uzbekistan, the government uses a technique called DNS hijacking to divert users from banned sites to so-called "modified mirrors", fake versions similar to the originals in most respects, but containing misinformation or black propaganda. Without some technical knowledge, the substitution is hard to spot. Dissidents such as Shi Tao now face a matrix of government, technology and corporate power which represents a fundamental change in the way censorship is practised and experienced around the world.

Beyond vague notions of "corporate social responsibility" it is clear that global information companies do not feel they have any obligation to be open or transparent, let alone to maintain any kind of public space for debate or dissent. Indeed, in a world where foundational technologies such as search algorithms are valuable intellectual property in themselves and messages travel through chains of privately owned systems operating under different national laws and local technical protocols, it can be almost impossible to know whether information is being buried or blocked, let alone what, how and by whom. Even in markets with no overt state censorship, the threat of legal action may be enough to take controversial information offline, a tactic frequently employed by corporations against critics or whistle-blowers. Payments are routinely made and taken for positioning in search rankings: money buys visibility, not accuracy or fairness.

We appear to be moving towards a world with a privatised knowledge infrastructure, where indexing, storage and transmission are all performed by unaccountable entities engaged in what Human Rights Watch has aptly termed a "race to the bottom" for access to eyeballs and renminbi. What price market share in a world dancing to a Chinese economic tune? Whose organs get harvested? Whose liver will your board of directors eat? Nostalgia for disinterested notions of truth or intellectual independence will not suffice to preserve freedom of speech through the coming century. It will take concerted political action and a revitalisation of the notion of an "unowned" public sphere, something which will be fought tooth and nail by both state and corporate interests. We are already living through a period of enclosures, in which the knowledge commons are being rapidly fenced off.

Social panic about terrorism and paedophilia means that there is strong public support in most western democracies for mandatory state access to private communications. In the permanent state of pseudo-war under which we now live, interior ministers constantly remind us that civil liberties must be balanced against the exigencies of security. Technologies such as strong encryption and anonymous remailing must, they tell us, be kept out of the hands of the public. Employment of such technologies must constitute reasonable cause for surveillance. Encryption keys must be handed over on demand. Local ISPs must be forced to surrender data when required, preferably through real-time automated "black box" monitors, connected to their systems. Monitoring of voice and data traffic by the US (and perhaps, one day, by China) must be facilitated. The list goes on.

Unfortunately for us complacent beneficiaries of liberal democracy there is a paradox at work here. The technologies that provide anonymity to the paedophile and the terrorist also protect the political dissident and the whistle-blower. The encryption that impedes government surveillance of its citizens is also vital to the global banking system - an interesting area where corporate and state interests are in direct opposition.

For human rights campaigners it is time to move beyond the sphere of protest and lobbying into an active engagement with information technologies, putting anti-censorship tools into the hands of those who need them, providing services and support to dissidents rather than campaigning for their release after they have been imprisoned. Preservation of the global public sphere, individual civil liberties at home and the safety of dissidents in totalitarian regimes are now inextricably linked. It's not an easy knot to untangle, but we must try.

· Extracted from Another Sky: Writings from Prison around the World in association with English PEN. Published on April 12